Customarily, when a screw is tightened by a power driver or an electric screwdriver, the screw is sometimes driven by the use of a magnet to hold a screw to a bit of an electric screwdriver.
However, since such screw tightening work attaches the head of a screw to the front end of an electric screwdriver, for example, a screw needs to be held by fingertips of an available hand. Or, if a screw is not screwed tightly, a screw needs to be supported by fingertips of an available hand. Such a supporting action occupies both hands of an operator, resulting in low work efficiency. Also, in a work environment with an unstable ground such as a construction site, it has always been inconvenient.
Since a screw that is driven by the front end of a driven screwdriver is not necessarily tight or not necessarily stable, a screw must be carefully tightened for small parts. As a result, an operator has to work hard and he or she tends to get more exhausted.
In order to solve the above problems with known technology, it is known to stabilize a screw at the driving end of an electric screwdriver by vacuuming the screw by the suction pressure of the air in Japanese Patent Application Hei 10-375218.
However, the above requires an air suction pressure generating apparatus. It causes a problem of requiring new equipment investment if the work place does not have such equipment.
Other screw capturing devices with manually positioned spring fingers mounted on a screwdriver are known or with automatic screw catchers of different types.
An object is to provide a screw capturing device for use with a power driver or an electric screwdriver that does not require vacuum, can be easily attached to or detached from a bit of an electric screwdriver, and does not interfere with, but makes easier, screw tightening work.
Furthermore, the invention can be made to correspond to several types of screws with different sizes, firmly capture the head of the screw, and can securely perform the screw tightening work.
Another object is to provide a screw capturing apparatus for a power driver or an electric screwdriver that enables visual confirmation that the head of the screw is captured and can perform the screw tightening work securely and safely.
And, another object is to provide a screw capturing apparatus for a power driver or an electric screwdriver that is light and small, and its components can be easily manufactured and assembled.
Because of the above construction, this apparatus can be adjusted to match the size of the screw. By operating the caliper adjustment means, the inner diameter of the opening part of the screw capturing device can be adjusted to match the diameter of the head of the screw to be tightened. When the front end of a power driver or an electric screwdriver is used with a screw supplier and the head of the screw is inserted into the opening between them, the elastic holding fingers hold the head of the screw. When the screwdriver that holds the screw is moved toward an object to place the screw in a screw hole of the object and the screwdriver is pushed toward the screw hole to turn the bit, the holding fingers receive the force in the opposite direction from the direction of a screw insertion as the screw enters into the screw hole. Since the holding fingers are pushed against the spring loaded means, it will not be a hindrance to screw tightening. When the screw is tightened and the screwdriver is detached from object, the holding fingers return to the initial position by the spring loaded means.
It is preferred that the screw capturing device is formed entirely of transparent materials or at least the holding fingers. If the holding fingers are transparent, the screw can be tightened securely and safely while visually confirming the status of screw capturing.